The radius of the circle x + y + x + c = 0 passing through the original point| What is it?

The radius of the circle x^(2) + y^(2) + x + c = 0 passing through the origin is

A chord of the circle x^2 + y^2 - 4x - 6y = 0 passing through the origin subtends an angle arctan(7/4) at the point where the circle meets positive y-axis. Equation of the chord is

Find the locus of the mid points of the chords of the circle x^2 + y^2 -2x -6y - 10 = 0 which pass through the origin.

Equation of the diameter of the circle x^(2) +y^(2) - 2x + 4y = 0 which passes through the origin is

The diameter of the circle concentric to the circle x^(2) + y^(2) + 4x - 2y = 20 and passes through the origin is -

Find the radius of the circle which passes through the origin and the points (a, 0) and (0, b).

Find the radius of the circle passing through (6,0), (0,8) and origin .